Rapidity correlations of protons from a fragmented fireball

We investigate proton rapidity correlations for a fireball that fragments due to non-equilibrium effects at the phase transition from deconfined to hadronic phase. Such effects include spinodal fragmentation in case of first order phase transition at lower collision energies, and cavitation due to sudden rise of the bulk viscosity at the crossover probed at RHIC and the LHC. Our study is performed on samples of Monte Carlo events. Correlation function in relative rapidity appears to be a sensitive probe of fragmentation. We show that resonance decays make the strength of the correlation even stronger.